1. Field of Invention
This invention relates to dispensing attachments for tools and, in particular, to an attachment for a hand-held, pneumatically-operated nailing gun which individually dispenses tin tags which are fastened to a roof by a fastener discharged from the nailing gun.
2. Brief Description of the Prior Art
The building code in certain jurisdictions requires tin tags (also referred to as roofing washers, plates or disks) to be placed at specified distances on the roof to securely fasten an overlay of black paper or the like to a wooden roof structure. It is currently the custom to hand place the tin tags on the overlay and to nail the tin tag to the roof using a pneumatically-operated hand-held nailing gun such as the Hitachi Nailer, Model NV45AB. This method, however, has several disadvantages and drawbacks. Because the typical tin tag has a diameter of approximately 1.625 inches, it is difficult for the nailing gun operator to center the nail on the tin tag. If too far off center, the nail causes the edges of the tin tag to become raised and these raised edges can then puncture the overlay. Also, hand placement of the tin tags presents a serious safety hazard to the user of the gun. Since the tin tag is placed by hand, the operator's fingers are frequently near the barrel of the nailing gun and it is not uncommon for the nailing gun operator to inadvertently shoot a nail into his finger.
Attachments to air powered tools for dispensing workpieces into a position where they can be pierced by a fastener driven by the tool are known in the patented prior art, as evidenced by the patents to Munn U.S. Pat. No. 3,734,377, and to Beach et al, U.S. Pat. No. 5,042,142.
The Munn patent discloses a part feeding attachment combined with a hand-held pneumatically-powered driving tool which advances one part at a time into position for piercing by a fastener delivered by the tool. This device uses the residual exhaust air pressure from the driving tool to actuate a pneumatically operated driver mechanism which is connected to a feeder which engages a single metal disk and positions it for piercing by the next succeeding fastener driven by the tool.
The Beach et al patent discloses a stand-up screw gun which individually dispenses stacked roofing washers and drives a fastener therethrough. This machine, however, requires a special ribbed washer designed to prevent the washers from adhering in order to operate without jamming.
These devices have not achieved wide spread use in the roof construction industry because they require alteration or modification to the commercially available nailing guns currently used in the roofing industry, must he purchased as a preassembled integral unit with a new nailing gun, are prone to jamming, or cannot be used with commercially available tin tags.
There remains a need, therefore, for a light weight dispensing attachment which can be easily connected and disconnected from the hand-held roofing guns currently being used in the roofing industry and which can operate using commercially available tin tags without jamming. The present invention was developed to overcome these and other drawbacks of the prior art devices.